BACKGROUND Besides noise, mechanical vibration of a general effect (whole body vibration), is an important physical risk factor that occurrs in the farmers' work environment. The vibration occurs on the seats of agricultural vehicles in motion, during the performance of specified field and transportation work tasks. MATERIAL AND METHOD The study covered the measurements of time schedules of a...

Anti-vibration units have been developed to realize micro-vibration circumstance. Recently, the anti-vibration units using the piezo-elements have been widely developed. In these units, acceleration sensors were ordinarily used. However, in the literature 3), velocity sensors were attached to detect the vibration of structure. Then, the state-feedback theory was naturally applicable to the anti...

OBJECTIVES To investigate the acute response of finger circulation to vibration with different combinations of magnitude and duration but with the same "energy equivalent" acceleration magnitude according to current standards for hand transmitted vibration. METHODS Finger skin temperature (FST) and finger blood flow (FBF) were measured in the middle fingers of both hands of 10 healthy men who...

Bone cells are deformed according to mechanical stimulation they receive and their mechanical characteristics. However, how osteoblasts are affected by mechanical vibration frequency and acceleration amplitude remains unclear. By developing 3D osteoblast finite element (FE) models, this study investigated the effect of cell shapes on vibration characteristics and effect of acceleration (vibrati...

This paper presents the overall design of an industrial vibration transmitter using Micro Electro Mechanical System (MEMS) capacitive accelerometer. It describes the accelerometer sensor interfacing circuit, rms-to-dc converter and voltage to current loop converter circuit design, calibration procedure and mounting methods. The industrial vibration transmitter output can be customized to obtain...

In order to obtain the useful information from the raw data which contain the state data reflecting the structure condition and the noise, de-noising and feature extraction techniques based on Wavelet analysis were studied. An improved wavelet thresholding algorithm to eliminate the noise for vibration signals was proposed. Comparison analysis with other thresholding algorithms shows that the n...

The dynamics of the jamming transition in a three-dimensional granular system under vertical vibration is studied using diffusing-wave spectroscopy. When the maximum acceleration of the external vibration is large, the granular system behaves like a fluid, with the dynamic correlation function G (t) relaxing rapidly. As the acceleration of vibration approaches the gravitational acceleration g ,...

Low frequency vibration occurs especially in ground transportation, either as a cause in adjacent environment or within the vehicle itself. The piezoelectric accelerometers commonly used for vibration measurement are not suitable, hence other sensors capable of measuring accelerations down to sub-hertz region have to be used. Based on some previous experience with MEMS acceleration sensors a th...

A fuzzy logic based digital sinusoidal acceleration waveform amplitude controller for a PC based electrodynamic vibration actuator is presented. The fuzzy logic control (FLC) purpose is to reproduce pre-defined sinusoidal acceleration amplitude at the vibration table of a vibration actuator system. Sinusoid vibration profiles (sine and linear sine sweep) are considered for a closed-loop control...

Human health and comfort under whole-body vibration depend on the level, frequency, direction, location, and duration of the acceleration. The international standard ISO 2631-1 [1] specifies a method of evaluation of the effect of exposure to vibration on humans by weighting the root-mean square (r.m.s.) acceleration with human vibration sensitivity curves. There are six frequency-weighting cur...